its too tragic and sad
its a unique dynamic, haruka was her first love, although a love that has no future.
there was genuine friendship within the three.somehow the trio has memories that is very personal and irreplaceable to themselves.
in the end tomboy mc and male mc ended up together, it makes sense how the closest thing they can remember haruka is being with each other so its like a commemoration/sign of dedication that they're still the same group for their friend not to be forgotten but resonate throughout the rest of their lives